An open loop compensation technique for reducing supply sensitivity of CML ring oscillator

The causes of supply induced noise are investigated and a circuit technique that reduces the supply sensitivity of CML ring oscillator is presented. This technique applies a current bias circuit with negative supply sensitivity to compensate the intrinsic positive sensitivity of VCO and alleviate the impact of supply voltage fluctuation. A prototype chip is fabricated in a 180 nm CMOS process to prove its rejection of supply noise.